This invention relates generally to devices or apparatus for obtaining useful work from the energy of waves.
The amount of energy or power available in waves is enormous and this power is generally recognized by the damage caused. Thus, waves are usually regarded as a hindrance rather than an asset. For example, at Wick Breakwater in Scotland a block of cemented stones weighing 1,350 tons was broken loose and moved bodily by waves. Several years later, a replacement pier weighing 2,600 tons was carried away. In other instances, a concrete block weighing 20 tons was lifted vertically to a height of 12 feet and deposited on top of a pier 5 feet above the highwater mark; stones weighing up to 7,000 pounds have been thrown over a wall 20 feet high on the southern shore of the English Channel; and on the coast of Oregon, the roof of a lighthouse 91 feet above the water was damaged by a rock weighing 135 pounds.
Heretofore this enormous amount of power available in the world's oceans has been largely ignored. One reason for this lack of utilization of the available energy in the world's oceans is their very power. In other words, most devices which have been designed for capturing or converting the energy of waves to useful work have been destroyed or damaged by that very energy. This is at least partly due to the irregularity of waves which can cause jerky or irregular motion of wave energy devices. Moreover, storms frequently occur during which time wave action can become violent, thus destroying installations erected for converting the energy of the waves to useful work. Other prior art devices are not efficient in operation and convert only a very small portion of the available wave energy. For example, the actual propagation or movement of water particles in a lateral direction is only about one percent of the velocity of travel of waves. Thus, while devices floating on the surface of a body of water may be utilized to extract some of the energy of the waves themselves, these devices are not able to extract energy from the moving water itself.
Prior art devices range from elongate cylinders or like structures bobbing at the surface of the body of water for driving a propeller carried thereby, through so-called air turbines which comprise floating bodies at the surface with open bottom chambers into which waves are permitted to rise and fall for alternately compressing air in chambers to drive a turbine, up to complex bodies specifically configured to obtain rotational movement from the action of waves and moving water particles thereon to drive turbines. These last devices are commonly referred to as Salter's Duck, for example, and are more fully described on pages 21, 22, 23 and 24 of the January, 1976 issue of THE NAVAL ARCHITECT.
All such prior art devices capture or convert only a small portion of the available power in waves and in many cases are not durable enough to withstand the forces encountered in the ocean's waters or are not cost efficient.
The present invention, on the other hand, provides a unique structure which floats at the surface of a body of water and is constructed to convert the rolling or orbital motion of water particles in the waves into a linear flow of water and to then accelerate the linear flow without using any mechanical means or process. The accelerated flow is then utilized, inter alia, to drive a water wheel, turbine or the like for extracting power from the moving body of water. The linear flow of water so created may be utilized for a variety of other industrial purposes, such as extinguishing waves or collecting substances contained in the water. The densification of the energy in the waves by converting it to linear flow and then accelerating the linear flow without using any mechanical means or process results in a substantial increase in the amount of power or energy extracted from the waves, since the energy varies in proportion to the square of the velocity of the water (E=1/2MV.sup.2). Moreover, the device or apparatus according to the invention includes structure which is caused to pitch and heave with wave movement and has means for extracting power from the waves as a result of the pitching and heaving movement. Additionally, the apparatus of the present invention is normally disposed beneath the surface of the body of water and is free floating and is adapted to weather storms and the like without damage thereto, and in fact, the power extracted from the waves by the present invention remains smooth and substantially uninterrupted during varying conditions of the surface of the body of water.